Synthesis of carotenoids by Rhodotorula rubra GED8 co-cultured with yogurt starter cultures in whey ultrafiltrate

Abstract

Two cultures, a yeast ( Rhodorula rubra GED8) and a yogurt starter ( Lactobacillus bulgaricus 2-11+ Streptococcus thermophilus 15HA), were selected for associated growth in whey ultrafiltrate (WU) and active synthesis of carotenoids. In associated cultivation with the yogurt culture L bulgaricus 2-11+S. thermophilus 15HA under intensive aeration (1.3 l(-1)min(-1) air-flow rate) in WU (45 g lactose l(-1)), initial pH 5.5, 30 degrees C, the lactose-negative strain R. rubra GED8 synthesized large amounts of carotenoids (13.09 mg l(-1 )culture fluid). The carotenoid yield was approximately two-fold higher in association with a mixed yogurt culture than in association with pure yogurt bacteria. The major carotenoid pigments comprising the total carotenoids were beta-carotene (50%), torulene (12.3%) and torularhodin (35.2%). Carotenoids with a high beta-carotene content were produced by the microbial association 36 h earlier than by Rhodotorula yeast species. No significant differences were notd in the ratio between the pigments synthesized by R. rubra GED8+ L. bulgaricus 2-11, R. rubra GED8+ S. thermophilus 15HA, and R.rubra GED8+yogurt culture, despite the fact that the total carotenoid concentrations were lower in the mixed cultures with pure yogurt bacteria.

Carotenoids from Rhodotorula and Phaffia: yeasts of biotechnological importance

“…Later, these authors demonstrated that the cell wall fractured PhaYa yeast containing high concentrations of astaxanthin can be a useful source of astaxanthin for the modiWcation of meat color, thus meeting consumer preferences in relation to the qualities of poultry meat [159]. The [24] eVect was heightened by supplementing fractured yeasts in the broiler feed in proportion to dietary astaxanthin concentration. Similarly An et al [149] concluded that a astaxanthin in yeast (X. dendrorhous) prepared by spray drying and Xat-roller milling was well absorbed by laying hens and was successfully used as a pigmentation agent in animals.…”

“…A widespread natural substrate is milk whey containing lactose as a carbon source. Carotenoid synthesis by lactose-negative yeasts (R. glutinis, R. rubra strains) in whey ultraWltrate can be accomplished: by enzymatic hydrolysis of lactose to assimilable carbon sources (glucose, galactose) thus providing the method of co-cultivation with lactose-positive yeasts (Kluyveromyces lactis), producers of -galactosidase [67] or by creating conditions under which lactose is transformed into carbon sources (glucose, galactose, lactic acid) easily assimilated by the yeast when they were grown in association with homofermentative lactic acid bacteria or yogurt starter culture [15,16,24]. The maximum carotenoid yields for the microbial associations [R. rubra + K. lactis; R. glutinis + Lactobacillus helveticus; R. rubra + L. casei; R. rubra + (L. bulgaricus + Streptococcus thermophillus)] were, as follows: 10.20, 8.10, 12.12, 13.09 mg/ l, respectively.…”

Chemical composition, functional properties and processing of carrot—a review

“…The effect of different pre-treatments like blanching solution and blanching times (1-5 min) on the physico-chemical parameters and quality of carrot juice have been studied by Bin-Lim and Kyung-Jwa (1996) and Sharma et al (2009) Source: Suman and Kumari (2002) respectively. Carrot juice is also used by yoghurt industry Simova et al 2004). Blending of yoghurt with carrot juice produces a nutritionally rich food (Ikken et al 1998;Raum 2003).…”

Carbohydrate components of culture media as determinants of the Rhodosporidium diobovatum IMB Y-5023 yeast metabolism

“…It is known that the growth and carotenogenesis of yeasts can be affected by many factors: temperature, pH, aeration, light, as well as the nature and concentration of sources of carbon, nitrogen, minerals and vitamins (Libkind et al, 2008;Simova et al, 2004). The type and concentration of carbon sources is one of the main factors limiting not only the growth of yeast cells, but also the synthesis of carotenoids.…”